I read somewhere here that the Navio+ “added HAT support”, which according to the RasPi Foundation requires a ROM chip to be connected to GPIO0 and 1 (which then become reserved for reading the hardware ID and default pin configurations).
When writing the Windows drivers, I will try to check for such things to give some kind of plug and play. But to save wasting time, can @emlid4 please confirm:
- Is it really a “HAT”?
- If yes, what sort of data/file/Id should I get back when reading the ROM?
- Do you also provide the default hardware pin configuration (optional in the specification). Which would mean it would never be necessary to check and set the GPIO direction/resistance for “used” Navio+ pins. Also do you set any defaults for the other “free” pins.
Of course I’ll take time to read the whole HAT standard/firmware guide so I can get this sort of information. It appears the Windows IoT firmware does not expose this (but I will check properly) even though when explaining why the GPIO pins are reserved it mentions the firmware does something with it.